By Dan Frommer.From the archives.Thursday, September 15, 2011 at 9:57 am.

Netflix investors overreact to new forecast: The streaming numbers are what matters

Netflix investors are selling off this morning — the stock is down 15% — after the company issued new subscriber guidance for Q3 (PDF), reflecting the reaction to its price increases, announced in July and effective for existing subscribers on Sept. 1. The backlash seems to have caught Netflix — and the Street — by surprise. The new forecast includes 1 million fewer total subscribers than before: 24 million vs. 25 million previously.

Here’s the thing, though. The future of Netflix is in its streaming business — not its business of mailing DVDs to people via the U.S. Postal Service. And Netflix only trimmed its forecast for streaming customers by 0.2 million, or 1%. The biggest cut, meanwhile, is 0.8 million DVD-only subscribers, or 27% of that customer base. But that’s Netflix’s old business, not its new one.

If anything, Netflix can take these numbers to Hollywood and say: Look, people don’t want DVDs anymore, either stream your best stuff on our site or good luck selling those DVDs at Borders. (And Netflix even says that its financial guidance for the quarter is unchanged.)

No doubt, Netflix still has a huge challenge ahead: Building the best streaming service on the planet, and convincing Hollywood to participate with its newest and best content. (With well-funded competition on the rise!) While fewer DVD-only households may be a short- to medium-term financial challenge for Netflix, it’s certainly not a long-term strategic problem.

Now, I’m not one to say where Netflix shares should be priced. But based on today’s news alone, the company’s future doesn’t seem to be worth 15% less that it was yesterday. (Reminder: I do not own any individual stocks. If that ever changes, it would be listed on my about page.)